Elevator-brake.



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A. H, MEECH.

ELEVATOR BRAKE.

APPLICATION men JULY \2. 1910.

Patented Nov. 28, 1916.

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A. H. MEECH.

v ELEVATOR BRA KE. APPLlCATiON FILED JULY 12, WW.

1;}? Patented Nov. 28, 1916.

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ALFRED H. MEECH, 0F CHATI-IlhM, 15321 2 011,151, ASSIGNOR T0 ELEVATOR AIR BRAKE COMPANY, A GORPGBATION 0F MISSOURI.

ELEVATOR-BRAKE.

Specification of Letters Patent.

Patented Nov. 28, 121.65.

Application filed July 12, 1910. Serial No. 571,576.

To all whom it may concern Be it known that I, ALFRED H. MEECH, a citizen of the United States, residing at Chatham, in the county of'Columbia and State of New York, have invented certain new and useful Improvements in Elevator- Brakes, of which the following is a full, clear, and exact description.

This invention relates to elevator brakes and has special reference to the mounting of the brake-shoes of such installations- The invention is designed to be used with elevator air-brakes of-the type set forth in my prior Patents Nos. 722,736, 860,986 and 962,037, but is, however, applicable to all elevator brakes and similar installations where a car is guided slidably on rails.

An elevator ascending and descending in a shaft represents at times immense'potential and kinetic energy. For example, if the suspended cables of a heavily loaded car break when the car is at the top of a shaft, the car will descend with a steadily increasing kinetic energy, which may amount to thousands of foot-pounds in a few seconds. Hence the importance of a brake of great certainty and holding power in case a brake is relied upon to arrest the descent of a car in the event of an accident. In my experiments I have evolved a brake having adequate holding power and certainty of action to stop an elevator car even if very heavily loaded and sliding on greased and polished rails, and which will not abrade or destroy the rails by numerous or even practically continuous applications.

The essential principle of the mechanism depends upon the application of the braking power to the brake shoes in such a manner as to automatically make the shoes tend to set themselves against the rails, and thereby assist in the holding action, which is commenced or instituted, in the preferred form of my invention, wholly by air pressure and toggles, so that the greater the load upon the car, the greater will be the grip of the brake-shoes upon the guide rails.

The present invention also includes a special construction of power levers or toggle levers, which secure certain functions later pointed out. With these and other objects in view, my invention consists in the features of construction and combination as hereinafter set forth and claimed.

In the drawings: Figure 1 is an end elevation of an elevator brake embodying the principles of my invention, the guide rail of the elevator shaft being shown in section. Fig. 2 is a horizontal sectional view of the same on the line IIIT of Fig. 1. Fig. 3 is a partly sectional view showing the brake shoes in their open or non-engaging position on the guide rail. Fig. 41 is a similar view showing the brake-shoes applied or clamped upon the guide rails. Fig. 5 is a detail side elevation of one of the shoes.

Referring to the drawings in which like parts are designated by the same reference sign, 1 designates a frame constituting the body or support of the brake.

2 is a power cylinder which I preferably form integral with the supporting frame 1.

3 designates a piston, moving in the power cylinder 2 and having a piston-rod 4 provided with a cross-head 5 outside the cylinder-head 6. This cylinder-head guides the stroke of the piston-rod 4. The piston 3 is normally pressed to its innermost position the abutting faces 15 of said arms have an arcuate outline, the arcs being of such radii that the abutting faces impinge against each other at all times when the piston-rod 4 is pushed toward its outermost position in a manner to be hereinafter described. The outer ends of the two arms 12 are bifurcated and have pivoted therein the power levers 13 by means of the pins 14c. It is evident that the diverging arms 12 act together to form a toggle joint between the power arms 13 and the force and manner of the toggle action is dependent on the curvature and form of the arcuate faces 15. By properly shaping these faces 15 it is. possible to make the power factor of the toggle joint increase in a definite and regular manner. Besides this, the foregoing structure is a specially advantageous one in that no minor irregularities in the fitting of the parts or in the alinementof the guide-rails or like fixed parts in the elevator shaft can have any iefiect' on the working of the brake, since the links 9 are freeto swin from side to'side and always work as above described whether they are'inclined or in parallelism with the hue I of movement of the piston. It is also to be observed that the links 9 and arms 12 are prevented from bending or buckhng in about their connecting pivots 11 into positions directly opposite the operative 01 nor- I mal positions shown, by, the engagement of the power arms 18 with the shoulders 12' of the bifurcated portions of levers 12.

20' denotes brake-shoes, of which two are provided to grasp alixed part or member of the elevator'run-way; This fixed part, designated A, is preferably the guide-rail,

but may be a brake rail, cable or the like.

' ,The shoes are operated by the power arms 13, and the essential principle or characteristic of the shoes 20. is that they tend to automatically set or wedge themselves 'against'the guide rail or fixed member A whenever the power is applied thereonfrom thepower arms. 'As will later appear, I

may employ different types of power arms 7 and different types of brake-shoes embodying the principlesof the present invention. With the form of power arms 13, as already described, I prefer to employ pivoted brake shoes adapted to swing about fixed pivot studs 22 which project from the frame or body 1. These brake'shoes are not pivoted to the-studs 22 in the manner of an ordinary pivot or hearing support, but have inclined slots 28 having a widthwise diameter equal to the diameter of the pivot studs 22 anda lengthwise diameter considerably greater than'the diameter of said pivot studs thereby permitting a certain independent movement of the shoes on the pivot studs in the direction of the inclination of these slots.

"lhe'inclination of the slots is such as to cause the shoes 20 to approach one another under the influence of any upward pressure exerted thereon. Each of the shoes 20 has a pivot connection 24 with what be termed shoe links 27, The shoe links 27 are pivoted at 26 to the forward extremities of the'power arms 13. In accordance with my present invention, the shoe links 27 are not directly pivoted to the shoes 20 by their pins 2%, but move in inclined slots or guideways '25 within said shoes, the inclination of these slots being opposite to that of the slots 23.

. The shoes 20 may be lined with any suitable friction. lining 28, for which I prefer camfels hair fabrlc 1n practice.

, i The use and operation of this form of my invention is as follows: Assuming that an application of the brakes becomes necessary with the car ascending or descending, air pressure is supplied to the cylinder 2, driving the piston 3 outward and expanding the diverging arms 12 in such a way as to separate the power a ms 13 and impel. the shoe tendency is strongly aided by the engagement of the lower portions of the friction linings with the sides of the fixed member when the car is descending, owing to the weight and movement of the car, which urges the shoes upward relatively to the car and in turn drives the upper ends of said shoes in toward the rail with tremendous force, the shoes moving inwardly with respect to studs 22 and the oblique slots 23 co-acting with said studs to exert a powerful wedge action. The relative up ard travel of the shoes allows each pin 24: to approach the inner end of its respective slot 25, so that the arms 12 are allowed to assume a position approaching alinement, resulting in a maximum toggle effect at this point in the apparatus which in turn increases the pressure upon the lower ends of the shoes and thereby still more strongly wedges the 3' upper ends of the shoes into engagement with the rail. Furthermore owing to the fact that the shoes are pivotally or oscillatably mounted upon the studs 22 there is some tendency for the lower ends of the l shoes to rotate inwardly toward the rail, in-

creasing the gripping action of the lower portions of the shoes and thereby further wedglng the upper portions agalnst the pivot studs. Thus the action of the device when descending is retroactively cumulative and the braking effect is enormous. This is most advantageous since the greatest braking effect is needed when a falling car is to be checked or stopped. When the brake is applied to an ascending car, or when applied to lock a stationary car, it operates less powerfully since the wedging action is to some extent opposed by the frictional engagement of the shoes and the fixed i 2 member or rail and the cumulative effect just described is absent. The brake, however, is nevertheless elfective in this case, since the force to be overcome is very materially less than in the case of a descending :3

or falling car, and the rocking toggle formed by the eccentric toggle arms 12 is sufficiently powerful to force the pins 24 inward in the manner above described and to thereby press the shoes upward attaining a proper wedge action. In either case whether the car be ascending or descending, it is quickly brought to rest.

It will be observed that the degree of the braking action when braking a falling car is somewhat dependent upon the speed and momentum of the car, being more efficient as the momentum increases, as is desirable.

Another advantage of the pin and slot connection 22, 23, between the shoes and the casing 1, is that it permits a lateral adjustment of the shoes when their faces are parallel to the faces of the fixed rail with which they contact; or in other words, after a shoe has been brought into contact with the fixed ail so that practically its entire surface is in contact therewith, the shoe may adjust itself bodily with respect to the power arm to compensate for any irregularity in the width of the fixed. rail or compensate for any wear occurring upon the shoes. In the construction shown in my former patents the shoes are pivoted upon the casing 1, but have no automatic lateral bodily movement with respect thereto, and it was found such a construction would not permit the entire surface of the shoe to rest against the rail when in contact therewith, especially if there was a slight difference in the thickness of the rail at various points along the elevator shaft, or if the shoe became worn, in which instance only a portion of the surface of the shoe would be in contact with the fixed rail. By mounting the shoe for a lateral, as well as a swinging movement upon its pivot, this objection is obviated, since after the shoe has been forced into intimate contact with the fixed rail so that its entire surface is in contact and parallel therewith, the shoe may still have a slight'bodily lateral movement sufficient to permit it to adjust itself and compensate for any irregularities due to the variations in the thickness of the rail or in the wear upon the shoe.

Having described my invention, I claim 1. In an elevator braking appliance, a fixed part, a pair of slidably pivoted shoes adapted to grip said fixed part, and means for initially moving said shoes into frictional engagement with said part, said means comprising members having pin and inclined guideway engagements with said shoes, said shoes moving laterally with re spect to said members, when the latter are operated.

2. In an elevator braking appliance, a fixed part, a pair of shoes adapted to grip said fixed part, means for impelling said shoes into engagement with said part, fixed. studs having an inclined slot connection with said shoes and links joined to said means and also having an inclined slot con nection with said shoes.

8. In an elevator braking appliance, a

' fixed part, a pair of power arms, a pair of fixed studs, shoes having slots converging upwardly toward the fixed part and receiving said studs, and links joining said shoes and said power arms, said links having a slidable connection with said shoes.

l. In an elevator braking appliance, a fixed rail, a member carried by the car, a pair of brake shoes adapted to engage the opposite faces of said rail, power arms mounted on said member one connected to each of said shoes and exerting when actuated, a pressure on said shoes substantially at right angles to the rail, means for actuating said power arms, said shoes also having an inclined slot and stud connection with said member permitting said shoes to adjust themselves laterally with respect to the rail independently of the power arms and of each other and causing the shoes to wedge themselves between the member and the fixed rail when the brake shoes are applied.

5. In an elevator braking appliance, a fixed rail, a member carried by the car, a pair of brake shoes adapted to engage opposite faces of said rail for a substantial portion of their length and loosely pivoted on said member to have a lateral movement with respect thereto and to be wedged between said fixed rail and member when the shoes are pressed against the rail, a pair of power arms and connections between said power arms and shoes for pressing said shoes against said rail.

6. In an elevator braking appliance, a fixed rail, a member carried by the car, a pair of brake shoes adapted to engage opposite faces of said rail for a substantial portion of their length, each shoe having a loose connection with said member comprising an inclined wall and a relatively fixed part cooperating therewith, a pair of power arms one connected to each of said shoes for pressing said shoes against said rail and exerting a pressure thereon substantially at right angles to said fixed rail, and means for actuating said power arms.

7. In an elevator braking appliance, a fixed rail, a member carried by the car, a pair of shoes adapted to engage opposite faces of said rail for a substantial portion of their length, a pair of fixed studs on said member, said shoes having inclined slots fitting over said studs, said slots of the pair of shoes converging upwardly, a pair of power arms, means connecting said shoes to said power arms for exerting a pressure upon said shoes substantially at right angles to the fixed rail when actuated and means for actuating said power arms.

8. In an elevator braking appliance, a

fixed rail, a member carried by the car, a

pair of shoes adapted to engage opposite faces of said rail for a substantial portion of their length, loose connections between each of said shoes and said member comprising an inclined Wall and a fixed part c0- In Witness he1'e0f,I subscribe my signaoperatlng thereW1th,. the lnchned Walls of ture, 1n the presence of two \vltnesses.

said "connections converging upwardly, Lu FRED H MFECH 'powere 'ing llIlkS connecting stud arms to J 5 said shoes for exerting a'pressure upon said Witnesses:

shoes substantlally at rlght angles'to sald WALDO M. GIIAPIN, r'zul, and means for actuatlng sald arms. VILLIAM C. LARY.

Copies ofj this patent may be obtained m five cents each, by addressing the Commissioner of Patents,

7 Washington, D. C.

It is hereby certified that the State of incorporation of the assignee in Letters Patent No. 1,206,350, granted November 28, 1916, upon the application of Alfred H. Meech, of Chatham, New York, for an improvement in Elevator-Brakes, Was

erroneously Written and printed as Missouri, whereas said State should have been Written and printed Maine, as shown by the records of assignments in this office;

and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 26th day of December, A. D., 1916.

R. F. WHITEHEAD,

[SEAL] Acting Commissioner of Patents. 

